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[Photographs: J. Kenji Lopez-Alt]

With the recent influx of a few new seafood restaurants in Brooklyn and my lifelong love of fried fish, I've been scouring New York for a great fish sandwich for the past few months. Unfortunately, my search has been relatively fruitless, turning up several good-tasting candidates, but not that captures that quintessential New England combo of crisp beer batter encasing tender, flaky white cod, tangy tartar sauce, and a creamy, crunchy mayo-based slaw all on a buttery steamed bun. Is that too much to ask?

Fresh off a frying bender from my Korean Fried Chicken testing, transporting this task to home seemed like a natural.

There's not much to a good fried fish sandwich. The real key is all in the batter. A traditional beer batter is made with lightly leavened flour and cold, bubbly beer. The idea is that a good, light, bubble-filled batter will act as an insulator, slowing down the transfer of heat from the ripping hot oil to the delicate fish. As the exterior batter dehydrates and browns, the fish on the inside steams ever so gently.

For this to work properly, you need a batter that is light in texture, and browns relatively quickly. That's where the beer comes in. First off, sugars present in the beer will increase the brownability of the batter, while its alcohol content makes it more volatile, helping it to escape the batter and thus cook faster than a water-based batter ever could. The bubbles are also essential—they create the tiny, tiny pockets inside a good batter that add to our perception of crunchiness—it's really just a little boost for the baking powder, which performs a similar function.

Rather than using straight-up flour for my batter, I use a combo of flour and corn starch, which reduces the amount of gluten formed—a protein network that can cause a batter to become leathery and tough. Gluten formation is increased with excessive stirring, so for the best batter, I find that mixing it with a whisk or a pair of chopsticks just until it barely comes together is the way to go. A few spots of raw flour are perfectly fine.

I experimented using a few different coating methods—pre-flouring before battering, battering the fish straight up, etc. I found that the most effective method—the one that gave the best balance between crispness and lightness was to give the fish a quick coat in the dry flour mixture, followed by a dip in the batter, then a second dip into the dry flour before lowering it into the fryer.

I admit, the method is not the neatest. You're going to end up breading your hands, and once the fish comes out of the drippy batter and back into the dry flour, it's important to work fast before it all starts to drip off. I find the easiest method is to drop the battered fish into the dry flour, throw some more flour on top to coat, then pick it up by scooping under it and tossing it back and forth between your hands to get rid of excess dry flour. From here, it goes straight into a wok (or Dutch oven) full of hot oil.

Finally, it's important to make sure your beer is ice cold for three reasons:

Cold liquids hold their carbonation better.

Cold liquids inhibit the formation of gluten.

The recipe only calls for 1 cup of beer, so you're gonna have to drink the leftovers.